“During the period of December 2004 to January 2005, Bacillus anthracis killed three wild chimpanzees (Pan troglodytes troglodytes) and one gorilla (Gorilla gorilla gorilla) in a tropical forest in Cameroon. While this is the second anthrax outbreak in wild chimpanzees, this is the first case of anthrax in gorillas ever reported. The number of great apes in Central Africa is dramatically declining and the populations are seriously threatened by diseases, mainly Ebola. Nevertheless, a considerable number of deaths cannot be attributed to Ebola virus and remained unexplained. Our results show that diseases other than Ebola may also threaten wild great apes, and indicate that the role of anthrax in great ape mortality may have been underestimated. These results suggest that risk identification, assessment, and management for the survival of the last great apes should be performed with an open mind, since various pathogens with distinct characteristics in epidemiology and pathogenicity may impact the populations. An animal mortality monitoring network covering the entire African tropical forest, with the dual aims of preventing both great ape extinction and human disease outbreaks, will create necessary baseline data for such risk assessments and management plans.”

The authors of the AJP paper used PCR, a way of amplifying genes, to screen for the presence of Anthrax genes from the bodies of dead primates. In their paper they tabulate the data from their assays, and show how they can differentiate between other apathogenic variants. They make a very convincing argument on the importance of tracking down the impact of anthrax because of its potential to lie dormant in the ground and infect for hundreds of years. That is crucial considering our best interests are to conserve and preserve these species for as long as we can; we don’t want another factor affecting that main goal.

All throughout last year we posted on how a virus, Ebola, has been decimating primates in the Congo… but we largely were unaware of the impact of other pathogens that are contributing to this die-of. As the authors of this paper advocate there is a necessity to understand other key players that are affecting the conservation of great apes.

4 thoughts on “The role of Anthrax in the Great Ape Die-Off”

If anyone knows if nonhuman primates are prone to the infections caused by Staphyloccus aureus as humans are, please tell me so I can answer a question posed by my professor. Thank you for your help. Or, if you can give me the name of an individual or organization that has this information, this would be equally deeply appreciated.

Hello Fred, you maybe interested in the following articles that have published studies on S. aureus in nonhuman primates… I can’t hook you up with any vet or microbiologist that knows the prevalence or symptoms of the infection:

“In late October, 1974, Staphylococcus aureus postoperative wound infection was recorded in a nonhuman primate (Macaca mulatta) which had recently undergone surgical operation. Infection in a second monkey appeared approximately 2 weeks later, and a clustering of 6 cases appeared over the next 3-week period. The clinical spectrum included septicemia in 2 monkeys and skin infection at the surgical incision site of several others. Investigation revealed a uniform and consistent association of a phage group II S aureus strain characterized as 3A/55/71. This strain was also found to be enzootic among other postoperative monkeys sharing or having shared a common postsurgical care unit with infected monkeys. Epizootiologic studies indicated that this unusually virulent S aureus strain probably was introduced by an infected monkey which underwent surgery earlier in the month and that additional monkeys became infected by animal-to-animal transmission. After appropriate control sanitary measures were instituted, no new infections occurred.”

“A successful experimental treatment for gram-positive sepsis to our knowledge has not been achieved. The objectives of this study were to develop a nonhuman primate model of lethal gram-positive sepsis employing the micro-organism Staphylococcus aureus and to determine the efficacy of treatment using monoclonal antibody (MAb) to tumor necrosis factor alpha (TNF). The antibody was administered intravenously, 15 mg/kg, 30 minutes after the beginning of a 2-hour infusion of S. aureus, 4 x 10(10) colony forming units/kilogram. The baboons infused with S. aureus demonstrated the release of the cytokines TNF and interleukin-6 (IL-6), but endotoxin was not observed in the plasma at any time. Treatment with antibody to TNF abolished the rise in serum TNF levels and reduced the increased levels of IL-6. Treatment with MAb to TNF prevented multiple organ failure and achieved permanent (> 7 day) survival of all baboons.”

“Eight coagulase-negative, oxidase-negative and novobiocin-susceptible staphylococcal strains were isolated from the gastrointestinal tracts of South American squirrel monkeys (Saimiri sciureus L.). These strains were differentiated from known staphylococcal species on the basis of 16S rRNA gene and hsp60 gene sequencing, and from the most closely related species by using DNA–DNA hybridization, ribotyping, whole-cell protein profiles and biotyping. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that these strains are members of the Staphylococcus aureus species group (99 % similarity) but are biochemically similar to Staphylococcus piscifermentans, from which they can be phenotypically distinguished by resistance to polymyxin B, acid production from D-mannitol, the inability to hydrolyse aesculin and DNA and the absence of -glucosidase. On the basis of these analyses, a novel species of the genus Staphylococcus is described, for which the name Staphylococcus simiae sp. nov. is proposed, with CCM 7213T (=LMG 22723T) as the type strain.”

This last one is about Staphylococcus simiae, a variant of S. aureus, as indicated in the abstract.